
My solution was to draw my own trains and put them online.
I started TrainShirts.net to fill the gap between Thomas shirts and...well...the rest of the kid-friendly-train-shirts that don't seem to exist. CafePress has been a great resource for me since 2002, and they allow store owners to upload original designs and offer them online. Aside from trains, I've had a few other offerings up for a long time. It's more fun than anything, but it also provides my sons with an endless supply of original shirts that they can wear to school and the Y.
Aside from providing designs with catchy phrases, there is also an entire section of designs that are simply pictures. Stop by the store and check out the designs. If you have any suggestions for new designs let me know.
Enjoy! KDC